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Reflectance Difference Spectroscopy Characterization of Al x Ga 1—x N‐Compound Layers
Author(s) -
Rossow U.,
Aspnes D.E.,
Ambacher O.,
Cimalla V.,
Edwards N.V.,
Bremser M.,
Davis R.F.,
Schaefer J.A.,
Stutzmann M.
Publication year - 1999
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/(sici)1521-3951(199911)216:1<215::aid-pssb215>3.0.co;2-3
Subject(s) - materials science , epitaxy , band gap , spectroscopy , anisotropy , reflectivity , diffuse reflectance infrared fourier transform , sapphire , characterization (materials science) , interference (communication) , optics , optoelectronics , crystallography , chemistry , layer (electronics) , nanotechnology , physics , laser , biochemistry , channel (broadcasting) , electrical engineering , engineering , quantum mechanics , photocatalysis , catalysis
We report reflectance‐difference spectroscopy characterization of Al x Ga 1— x N‐compound layers grown on sapphire and 6H‐SiC. We observe interference features below the bandgap, a derivative feature at the bandgap, and no signal or a broad feature above the bandgap. We present simulations of the data which are based on the assumption that the c ‐axis is tilted with respect to the surface normal, which results in an apparent bulk anisotropy in the hexagonal layers in normal‐incidence reflectance measurements. We discuss implications with respect to a model by Tersoff [1], who suggested the formation of macrosteps during epitaxy.